1. Field of the Invention
The present invention relates to sheet processing for stacking bundles of sheets which are shifted with respect to each other on a discharge tray.
2. Description of the Related Art
Conventional sheet processing apparatuses sort sheets or staples sheets. The sheet processing apparatus receives sheets from a copier or a printer one by one and stacks the sheets on a process tray. The sheet processing apparatus jogs the sheets on the process tray and staples the sheets on the process tray. Then, the sheet processing apparatus discharges the stapled sheets onto a discharge tray in a bundle. The sheet processing apparatus shifts the discharge tray after each discharge of a stapled bundle of sheets in order to shift the bundles of the sheets with respect to each other. That is, a bundle of sheets on the discharge tray are shifted with respect to each other, therefore, it is easy to separate the bundle of sheets from other bundles. When the stapled sheets are shifted on the discharge tray, the positions of the staples are deconcentrated, thereby preventing an unbalanced stack.
However, the stack of bundled sheets on the discharge tray becomes unstable because of the discharge tray moving. Furthermore, an extra wall for supporting the sheets on the discharge tray and a powerful motor for moving the discharge tray are needed in order to stack a large number of sheets. Therefore, a large number of sheets can not be stacked on the discharge tray without the extra wall and powerful motor being provided. But, the extra wall and powerful motor rise the manufacturer""s cost of the sheet processing apparatus. Furthermore, the powerful motor makes the sheet processing apparatus large.
An object of the present invention is to provide sheet processing for stacking sheets in a state the bundles of sheets are shifted with respect to each other on a discharge tray without moving the discharge tray.
In order to achieve the above object, the present invention provides sheet processing apparatus comprising a first tray for stacking sheets received from an image forming apparatus, a jogger for jogging the sheet stacked on said first tray at one of a plurality of jogging positions, a discharger for discharging the sheet stacked on said first tray, and a second tray for stacking the sheets discharged by said discharger.
Other objects and features of the invention will be apparent from the following description and the drawings.